1. Field of the Invention
This invention relates to a plastic reaction vessel for holding a small quantity of liquid, comprising a vessel body having an edge portion which defines an opening, a cover, and a connecting strip which is integral with and connects said edge portion and said cover, which cover has an outwardly protruding rim, which when the opening is closed by the cover is in contact with said edge portion of the vessel body along a substantial portion of the periphery, and which cover has a cylindrical skirt, which is adapted to be inserted into the vessel body through the opening and from which the outwardly protruding rim extends like a flange, and which is provided with a sealing lip at that end of the skirt which is insertable into the vessel body through the opening.
The invention is also applicable to a reaction vessel in which the outwardly protruding rim of the cover is provided at its outer edge with a depending flange, which is generally parallel to the cylindrical skirt, and is engageable with the edge portion of the vessel body.
2. Description of the Prior Art
Reaction vessels provided with a cover are known from Laid-open German Application No. 17 73 331. In such vessels, important advantages are due to the fact that the cover cannot be lost.
The laid-open German application mentioned above discloses also a cover havinga cylindrical skirt, which is adapted to be inserted into the vessel body through the opening therein and from which the outwardly protruding rim extends like a flange. The outwardly protruding rim of the cover is provided with a protruding grip, which is opposite to the connecting strip.
In connection with such vessels it is also known to provide the vessel body with an opening which flares upwardly like a funnel so that the cylindrical skirt can smoothly be inserted. That skirt may be provided with an external sealing lip for engagement with a substantially cylindrical seating surface on the inside of the vessel body below the opening which is defined by the edge portion of the vessel body.
In vessels of the type described hereinbefore, the depending flange formed on the protruding rim of the cover serves to guide the cover on the edge portions of the vessel body and improves the stiffness of the vessel.
Particularly because such reaction vessels are often shipped while holding a liquid the cover should be held in its closed position not only by the engagement of a sealing lip with the inside peripheral surface of the vessel body but means should be provided by which the cover is reliably held in its closed position so that the action of forces which are inadvertently exerted on the cover in a lateral direction or in a different direction will not stress the sealing portions to such a degree that leaks can occur.